Pump throwout device



NOV. 7, 1950 HEDQ-UISTY 2,528,653

PUMP THROWOUT DEVICE Filed Aug. 13, 1945 IIIIIII/iiII/IIIIIIIIII/IIIII/I/ fiden ibz jVzZZv/z/ THedguzlsi Patented Nov. 7, 1950 PUltIP THROWOUT DEVICE Milton T. Hedquist, Rock Island, 111., assignor to J. I. Case Company, Racine, Wis., a corporation of Wisconsin Application August 13, 1945, Serial No. 610,529

1 Claim.

This invention relates to a reciprocating pump, and more particularly to a device associated therewith for disengaging the fluid-displacing elements from the driving mechanism.

In connection with certain kinds of machinery, for example, farm machinery, such as tractorpropelled cultivators or combines, it is desirable to provide power-driven means for performing certain operations, e. g., lifting the cultivator shovels out of operative position into transport position or lifting the cutting apparatus of a combine from operative position to a position of nonuse. Hydraulic piston actuators have been provided for this purpose, the pressure liquid to which is supplied by means of piston pumps which are usually driven from some rotatable power-driven part of the machinery. There may be many periods of time in which the machinery will be used for purposes which do not require the use of the hydraulic power piston. If the pump which supplies liquid to the piston is allowed to run, provisions are made whereby this liquid is by-passed or recirculated after the power piston has moved to its extreme limit. However, if the pump is allowed to continue to run during periods when there is no need for hydraulic control, there results undue and unnecessary wear on the pump and the transmission from the driving source to the pump.

One of the objects of my invention is to provide manual selectively operable means for disengaging the drive member from the pump, thus doing away with the inevitable wear and tear on the pump and associated parts.

Another object is to provide means as aforesaid which, in the case of a pump having a plurality of drive mem bers driving a plurality of pumping pistons, is capable-of'disengaging all of said pistons simultaneously.'

Still a further object is to provide a device as aforesaid which may be adapted to pumps already existing with little or no alteration in the parts.

Another object of my invention is to provide a device as aforesaid in which the disengaging means is instantaneously operable from normal to disengaging position by a single manual movement, and maintainable in either of said positions by simple, positive means.

Further objects and advantages of the invention will be apparent from the description and claims.

My invention will be described as embodied in 2 modate a variety of farm implements operable in certain respects by a hydraulic cylinder and piston receiving fluid under pressure from the pump. However, it will be comprehended that the invention is capable of being incorporated in pumps for other uses.

In carrying out my invention in one form I provide a device for disengaging the reciprocable pumping elements from the driving cams, such device being selectively manually operable whenever it is desired that the pump be rendered inoperative. Such a device is described and broadly claimed in a copending application of Otto Schoenrock, Serial No. 610,515 filed Aug. 13, 1945, entitled Pump Throwout Device which application is assigned to the same assignee as the present invention.

The present invention is an improvement of the invention disclosed in the above application, which invention was made by the said Otto R. Schoenrock prior to my invention and I, therefore, do not herein claim anything shown or described in that application which is to be regarded as prior art.

One embodiment will be described and shown in the accompanying drawings in which latter:

Fig. 1 is a fragmentary perspective view of the device of the invention;

Fig. 2 is a fragmentary view showing the cam followers in engaged and disengaged positions with respect to the cams;

Fig. 3 is a fragmentary view to show the screw for locking the operating arm of the device, and indicated as in locked-out position; and

Fig. 4 is a cross-sectional view of the hydraulic cylinder and piston.

Referring to Fig. 1, there is shown a pump 9 associated with a tractor, for example, and comprising a body it cross-sectioned to reveal parts within, the body having a pair of cylinders H in which are adapted to reciprocate the pistons 12. Each piston is provided with an integral enlarged portion or head i3, and a coiled compression spring 14 individual to each piston and intermediate the head [3 and body in serves to urge the pistons normally outwardly of the body. By means of suitable valve means and conduits (not shown) the interior of each cylinder I! is connected to a flexible tube l5 entering the hydraulic cylinder I6. Since the nature of the means for delivering the fluid under pressure from the pump 9 to the cylinder it is not a limiting feature of my invention, further particulars thereof are deemed unnecessary.

The cylinder I6 is adapted to receive a piston 26 a driving force.

Pivotally mounted on a shaft 24 carried in the pump housing 25 is a pair of bell crank levers r followers 26, each comprising an arm 21 terminating in a, rounded head 28 adapted to bear against the outer face of an associated piston head l3. The other arm 3| of each follower carries at its extremity a roller 32 adapted to bear against its associated cam 33. Cams 33 are shown as of the common, simple, eccentric type and are aflixed to a shaft 34 which is driven from the engine of the tractor by suitable connections (not shown). By virtue of the displacement of the cams 33 on an angle of 180 with respect to each other, the pistons l2 are reciprocated alternately as is understood in the art.

It will now be apparent that as long as the shaft 34, which is continuously driven by the engine of the tractor, is rotating, the levers 26 will be oscillated about their shaft 24 to actuate the pump pistons l2 and to force fluid through the pump valve means and the controlling valve operating the flow of fluid to the cylinder 6. However, during a major portion of the operating time of the tractor, the pump 9 is not utilized, and it is desired to eliminate wear on the pump and its associated parts.

Accordingly I provide a bell crank 4| including one L-shaped arm 42 adapted to extend transversely of the arms 21 and integral with a collar 43 attached by means of the set screw 44 to the other L-shaped arm 45 of the crank 4|. The arm 45 includes a cylindrical portion 46 serving as a pivot for the crank 4| and journalled in the framework 25. To maintain the crank 4| in either of its two positions to be hereinafter detailed, there is provided in the collar 43 a pair of depressions 41 and 41a (Fig. 3) each adapted to be engaged alternatively by the pointed tip of the locking screw 48 threadedly inserted in the framework 25.

From the foregoing it will be seen that when the locking screw 48 is withdrawn from an aperture 41 or 41a the arm 45 may be grasped manualy to rock the crank 4| clockwise or counterclockwise to move the arm 42 between the two positions shown in Fig. 2. When the pump is to be operated normally the crank 4| will have been rocked counterclockwise so that the arm 42 will occupy the full line, cross-hatched position shown in Fig. 2 and the followers 21 are then freed to be oscillated by the cams 33. Thus the pump will operate to force fluid into the hydraulic system. When it is desired to throw the pump out of service the lever 45 is moved inanually to rock the crank 4| clockwise. Thus the arm 42 is actuated to the dottedline position shown inFig. 2, to bring it into contact with the followers 26 and to force the followers against the urging of the springs M to the dotted line position shown in Fig. 2. In that manner the rollers are moved out of the path of travel of the cams 33 to render the pump inoperative notwithstanding continued rotation of the shaft 34. It will now be apparent that when the crank 4| is moved to either of its two positions the locking screw 48 may be engaged with a depression 41 or 41a to prevent accidental dislodgment of the crank 4| from either of its two positions.

While I have shown particular embodiments of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made, and I therefore contemplate by the appended claim to cover any such modifications as fall within the true spirit and scope of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

A power pump construction comprising a plurality of pistons in parallel side by side formation having a common discharge passage, each piston having an operating head, a plurality of coaxially mounted two-armed rock levers, one for each piston, each having a rock arm for actuating an operating head, a cam shaft rotatable about an axis parallel to the axis of said rock levers having a plurality of eccentric cams for actuating the other arms of said rock levers, respectively, mounted on said cam shaft, said eccentric cams being angularly displaced about the axis of said shaft to provide a difference in phase of the pistons, and common manually operable abutment means engageable with one arm of each lever and movable from a position in which it does not hold the lever arms out of engagement with the eccentric cams to a position in which it does hold the lever arms out of engagement with the eccentric cams comprising a rock bar engageable and .disengageable with respect to an arm of each lever.

MILTON 'I. HEDQUIST.

REFERENCES CITED The following references are of record in the file of this patent:.

UNITED STATES PATENTS Number Name Date 1,530,756 Clagett Mar. 24, 1925 1,930,297 Welch Oct. 10, 1933 2,128,413 Hejduk et a1 Aug. 30, 1938 FOREIGN PATENTS Number Country Date 48,192 Germany 1889 

